This is an aggregated list of all your top queries running on all the nodes of your database cluster. The list can be ordered by Occurrence or Execution Time, to show the most common or slowest queries respectively. It is also possible to filter and review queries from one particular node.

ClusterControl gets the information in two different ways:

Queries are retrieved from PERFORMANCE_SCHEMA

If PERFORMANCE_SCHEMA is disabled or unavailable, ClusterControl will parse the content of the Slow Query Log

Toggle Query Monitor to ON to enable query monitoring. If Performance Schema is enabled, ClusterControl will use it to look for the slow queries. Otherwise, ClusterControl will parse the content of MySQL slow query log based on the following flow:

Start:

Start slow log (during MySQL runtime).

Run it for a short period of time (a second or couple of seconds).

Stop log.

Parse log.

Truncate log (new log file).

Go to Start.

The collected queries are hashed, calculated and digested (normalize, average, count, sort) and then stored in ClusterControl.

Attention

By using slow query log, there is a slight chance some queries will not be captured, especially during “stop log, parse log, truncate log” parts. You can enable Performance Schema if this is not an option.

If you are using the Slow Query log, only queries that exceed the Long Query Time will be listed here. If the data is not populated correctly and you believe that there should be something in there, it could be:

ClusterControl did not collect enough queries to summarize and populate data. Try to lower the Long Query Time.

You have configured Slow Query Log configuration options in the my.cnf of MySQL server, and Override Local Query is turned off. If you really want to use the value you defined inside my.cnf, probably you have to lower the long_query_time value so ClusterControl can calculate a more accurate result.

You have another ClusterControl node pulling the Slow Query log as well (in case you have a standby ClusterControl server). Only allow one ClusterControl server to do this job.

The Long Query Time value can be specified to a resolution of microseconds, for example 0.000001 (1 x 10 -6).

View current running queries on your database cluster similar to SHOWFULLPROCESSLIST command in MySQL. You can stop a running query by selecting to kill the connection that started the query. The processlist can be filtered out by host.

This page is auto-refresh every 30 seconds. You can change the refresh rate by clicking on Refresh rate dropdown at top right.

MySQL Server

The MySQL server from which the process is retrieved.

Kill [thread ID]

Click to kill the specific MySQL thread ID.

ID

Connection identifier number.

DB

Database name.

User

The MySQL user who issued the statement.

Exec T

The time in seconds that the thread has been in its current state.

Client

The hostname (or port if TCP/IP) of the client issuing the statement.

Info

The statement the thread is executing, or NULL if it is not executing any statement.

Command

The type of command the thread is executing.

State

An action, event, or state that indicates what the thread is doing, as explained in MySQL Documentation page.

Shows queries that are outliers. An outlier is a query taking longer time than the normal query of that type. Use this feature to filter out the outliers for a certain time period. After a number of samples and when ClusterControl has had enough stats, it can determine if latency is higher than normal (2 sigma + average_query_time) then it is an outlier, and will be added into the Query Outlier.

This feature is dependent on the Top Queries feature above. If Query Monitoring is enabled and Top Queries are captured and populated, the Query Outliers will summarize these and provide a filter based on timestamp. You can view the query history as old as one year ago.